java.awt.geom

Class Line2D

public abstract class Line2D extends Object implements Shape, Cloneable

Represents a directed line bewteen two points in (x,y) Cartesian space. Remember, on-screen graphics have increasing x from left-to-right, and increasing y from top-to-bottom. The storage is left to subclasses.

Since: 1.2

UNKNOWN: updated to 1.4

Nested Class Summary
static class	Line2D.Double This class defines a point in `double` precision.
static class	Line2D.Float This class defines a point in `float` precision.

Constructor Summary
protected	Line2D() The default constructor.

Method Summary
Object	clone() Create a new line of the same run-time type with the same contents as this one.
boolean	contains(double x, double y) Test if a point is contained inside the line.
boolean	contains(Point2D p) Test if a point is contained inside the line.
boolean	contains(double x, double y, double w, double h) Tests if the line contains a rectangle.
boolean	contains(Rectangle2D r) Tests if the line contains a rectangle.
Rectangle	getBounds() Gets a bounding box (not necessarily minimal) for this line.
abstract Point2D	getP1() Return the first point.
abstract Point2D	getP2() Return the second point.
PathIterator	getPathIterator(AffineTransform at) Return a path iterator, possibly applying a transform on the result.
PathIterator	getPathIterator(AffineTransform at, double flatness) Return a flat path iterator, possibly applying a transform on the result.
abstract double	getX1() Return the x coordinate of the first point.
abstract double	getX2() Return the x coordinate of the second point.
abstract double	getY1() Return the y coordinate of the first point.
abstract double	getY2() Return the y coordinate of the second point.
boolean	intersects(double x, double y, double w, double h) Tests if this line intersects the interior of the specified rectangle.
boolean	intersects(Rectangle2D r) Tests if this line intersects the interior of the specified rectangle.
boolean	intersectsLine(double x1, double y1, double x2, double y2) Test if this line intersects the line given by (x1,y1)->(x2,y2).
boolean	intersectsLine(Line2D l) Test if this line intersects the given line.
static boolean	linesIntersect(double x1, double y1, double x2, double y2, double x3, double y3, double x4, double y4) Test if the line segment (x1,y1)->(x2,y2) intersects the line segment (x3,y3)->(x4,y4).
static double	ptLineDist(double x1, double y1, double x2, double y2, double px, double py) Measures the shortest distance from the reference point to a point on the infinite line extended from the segment.
double	ptLineDist(double px, double py) Measures the shortest distance from the reference point to a point on the infinite line extended from this segment.
double	ptLineDist(Point2D p) Measures the shortest distance from the reference point to a point on the infinite line extended from this segment.
static double	ptLineDistSq(double x1, double y1, double x2, double y2, double px, double py) Measures the square of the shortest distance from the reference point to a point on the infinite line extended from the segment.
double	ptLineDistSq(double px, double py) Measures the square of the shortest distance from the reference point to a point on the infinite line extended from this segment.
double	ptLineDistSq(Point2D p) Measures the square of the shortest distance from the reference point to a point on the infinite line extended from this segment.
static double	ptSegDist(double x1, double y1, double x2, double y2, double px, double py) Measures the shortest distance from the reference point to a point on the line segment.
double	ptSegDist(double px, double py) Measures the shortest distance from the reference point to a point on this line segment.
double	ptSegDist(Point2D p) Measures the shortest distance from the reference point to a point on this line segment.
static double	ptSegDistSq(double x1, double y1, double x2, double y2, double px, double py) Measures the square of the shortest distance from the reference point to a point on the line segment.
double	ptSegDistSq(double px, double py) Measures the square of the shortest distance from the reference point to a point on this line segment.
double	ptSegDistSq(Point2D p) Measures the square of the shortest distance from the reference point to a point on this line segment.
static int	relativeCCW(double x1, double y1, double x2, double y2, double px, double py) Computes the relative rotation direction needed to pivot the line about the first point in order to have the second point colinear with point p.
int	relativeCCW(double px, double py) Computes the relative rotation direction needed to pivot this line about the first point in order to have the second point colinear with point p.
int	relativeCCW(Point2D p) Computes the relative rotation direction needed to pivot this line about the first point in order to have the second point colinear with point p.
abstract void	setLine(double x1, double y1, double x2, double y2) Set the coordinates of the line to the given coordinates.
void	setLine(Point2D p1, Point2D p2) Set the coordinates to the given points.
void	setLine(Line2D l) Set the coordinates to those of the given line.

Constructor Detail

Line2D

protected Line2D()

The default constructor.

Method Detail

clone

public Object clone()

Create a new line of the same run-time type with the same contents as this one.

Returns: the clone

Throws: OutOfMemoryError If there is not enough memory available.

Since: 1.2

contains

public boolean contains(double x, double y)

Test if a point is contained inside the line. Since a line has no area, this returns false.

Parameters: x the x coordinate y the y coordinate

Returns: false; the line does not contain points

contains

public boolean contains(Point2D p)

Test if a point is contained inside the line. Since a line has no area, this returns false.

Parameters: p the point

Returns: false; the line does not contain points

contains

public boolean contains(double x, double y, double w, double h)

Tests if the line contains a rectangle. Since lines have no area, this always returns false.

Parameters: x the x coordinate of the rectangle y the y coordinate of the rectangle w the width of the rectangle h the height of the rectangle

Returns: false; the line does not contain points

contains

public boolean contains(Rectangle2D r)

Tests if the line contains a rectangle. Since lines have no area, this always returns false.

Parameters: r the rectangle

Returns: false; the line does not contain points

getBounds

public Rectangle getBounds()

Gets a bounding box (not necessarily minimal) for this line.

Returns: the integer bounding box

See Also: Line2D

getP1

public abstract Point2D getP1()

Return the first point.

Returns: the starting point

getP2

public abstract Point2D getP2()

Return the second point.

Returns: the ending point

getPathIterator

public PathIterator getPathIterator(AffineTransform at)

Return a path iterator, possibly applying a transform on the result. This iterator is not threadsafe.

Parameters: at the transform, or null

Returns: a new path iterator

getPathIterator

public PathIterator getPathIterator(AffineTransform at, double flatness)

Return a flat path iterator, possibly applying a transform on the result. This iterator is not threadsafe.

Parameters: at the transform, or null flatness ignored, since lines are already flat

Returns: a new path iterator

getX1

public abstract double getX1()

Return the x coordinate of the first point.

Returns: the starting x coordinate

getX2

public abstract double getX2()

Return the x coordinate of the second point.

Returns: the ending x coordinate

getY1

public abstract double getY1()

Return the y coordinate of the first point.

Returns: the starting y coordinate

getY2

public abstract double getY2()

Return the y coordinate of the second point.

Returns: the ending y coordinate

intersects

public boolean intersects(double x, double y, double w, double h)

Tests if this line intersects the interior of the specified rectangle.

Parameters: x the x coordinate of the rectangle y the y coordinate of the rectangle w the width of the rectangle h the height of the rectangle

Returns: true if the line intersects the rectangle

intersects

public boolean intersects(Rectangle2D r)

Tests if this line intersects the interior of the specified rectangle.

Parameters: r the rectangle

Returns: true if the line intersects the rectangle

Throws: NullPointerException if r is null

intersectsLine

public boolean intersectsLine(double x1, double y1, double x2, double y2)

Test if this line intersects the line given by (x1,y1)->(x2,y2).

Parameters: x1 the first x coordinate of the other segment y1 the first y coordinate of the other segment x2 the second x coordinate of the other segment y2 the second y coordinate of the other segment

Returns: true if the segments intersect

See Also: Line2D

intersectsLine

public boolean intersectsLine(Line2D l)

Test if this line intersects the given line.

Parameters: l the other segment

Returns: true if the segments intersect

Throws: NullPointerException if l is null

See Also: Line2D

linesIntersect

public static boolean linesIntersect(double x1, double y1, double x2, double y2, double x3, double y3, double x4, double y4)

Test if the line segment (x1,y1)->(x2,y2) intersects the line segment (x3,y3)->(x4,y4).

Parameters: x1 the first x coordinate of the first segment y1 the first y coordinate of the first segment x2 the second x coordinate of the first segment y2 the second y coordinate of the first segment x3 the first x coordinate of the second segment y3 the first y coordinate of the second segment x4 the second x coordinate of the second segment y4 the second y coordinate of the second segment

Returns: true if the segments intersect

ptLineDist

public static double ptLineDist(double x1, double y1, double x2, double y2, double px, double py)

Measures the shortest distance from the reference point to a point on the infinite line extended from the segment. If the point is on the segment, the result will be 0. If the segment is length 0, the distance is to the common endpoint.

Parameters: x1 the first x coordinate of the segment y1 the first y coordinate of the segment x2 the second x coordinate of the segment y2 the second y coordinate of the segment px the x coordinate of the point py the y coordinate of the point

Returns: the distance from the point to the extended line

See Also: Line2D Line2D

ptLineDist

public double ptLineDist(double px, double py)

Measures the shortest distance from the reference point to a point on the infinite line extended from this segment. If the point is on the segment, the result will be 0. If the segment is length 0, the distance is to the common endpoint.

Parameters: px the x coordinate of the point py the y coordinate of the point

Returns: the distance from the point to the extended line

See Also: Line2D

ptLineDist

public double ptLineDist(Point2D p)

Parameters: p the point

Returns: the distance from the point to the extended line

Throws: NullPointerException if p is null

See Also: Line2D

ptLineDistSq

public static double ptLineDistSq(double x1, double y1, double x2, double y2, double px, double py)

Measures the square of the shortest distance from the reference point to a point on the infinite line extended from the segment. If the point is on the segment, the result will be 0. If the segment is length 0, the distance is to the common endpoint.

Returns: the square of the distance from the point to the extended line

See Also: Line2D Line2D

ptLineDistSq

public double ptLineDistSq(double px, double py)

Measures the square of the shortest distance from the reference point to a point on the infinite line extended from this segment. If the point is on the segment, the result will be 0. If the segment is length 0, the distance is to the common endpoint.

Parameters: px the x coordinate of the point py the y coordinate of the point

Returns: the square of the distance from the point to the extended line

See Also: Line2D

ptLineDistSq

public double ptLineDistSq(Point2D p)

Parameters: p the point

Returns: the square of the distance from the point to the extended line

Throws: NullPointerException if p is null

See Also: Line2D

ptSegDist

public static double ptSegDist(double x1, double y1, double x2, double y2, double px, double py)

Measures the shortest distance from the reference point to a point on the line segment. If the point is on the segment, the result will be 0.

Returns: the distance from the point to the segment

See Also: Line2D Line2D

ptSegDist

public double ptSegDist(double px, double py)

Measures the shortest distance from the reference point to a point on this line segment. If the point is on the segment, the result will be 0.

Parameters: px the x coordinate of the point py the y coordinate of the point

Returns: the distance from the point to the segment

See Also: Line2D

ptSegDist

public double ptSegDist(Point2D p)

Measures the shortest distance from the reference point to a point on this line segment. If the point is on the segment, the result will be 0.

Parameters: p the point

Returns: the distance from the point to the segment

Throws: NullPointerException if p is null

See Also: Line2D

ptSegDistSq

public static double ptSegDistSq(double x1, double y1, double x2, double y2, double px, double py)

Measures the square of the shortest distance from the reference point to a point on the line segment. If the point is on the segment, the result will be 0.

Returns: the square of the distance from the point to the segment

See Also: Line2D Line2D

ptSegDistSq

public double ptSegDistSq(double px, double py)

Measures the square of the shortest distance from the reference point to a point on this line segment. If the point is on the segment, the result will be 0.

Parameters: px the x coordinate of the point py the y coordinate of the point

Returns: the square of the distance from the point to the segment

See Also: Line2D

ptSegDistSq

public double ptSegDistSq(Point2D p)

Measures the square of the shortest distance from the reference point to a point on this line segment. If the point is on the segment, the result will be 0.

Parameters: p the point

Returns: the square of the distance from the point to the segment

Throws: NullPointerException if p is null

See Also: Line2D

relativeCCW

public static int relativeCCW(double x1, double y1, double x2, double y2, double px, double py)

Computes the relative rotation direction needed to pivot the line about the first point in order to have the second point colinear with point p. Because of floating point rounding, don't expect this to be a perfect measure of colinearity. The answer is 1 if the line has a shorter rotation in the direction of the positive X axis to the negative Y axis (counter-clockwise in the default Java coordinate system), or -1 if the shortest rotation is in the opposite direction (clockwise). If p is already colinear, the return value is -1 if it lies beyond the first point, 0 if it lies in the segment, or 1 if it lies beyond the second point. If the first and second point are coincident, this returns 0.

Parameters: x1 the first x coordinate y1 the first y coordinate x2 the second x coordinate y2 the second y coordinate px the reference x coordinate py the reference y coordinate

Returns: the relative rotation direction

relativeCCW

public int relativeCCW(double px, double py)

Computes the relative rotation direction needed to pivot this line about the first point in order to have the second point colinear with point p. Because of floating point rounding, don't expect this to be a perfect measure of colinearity. The answer is 1 if the line has a shorter rotation in the direction of the positive X axis to the negative Y axis (counter-clockwise in the default Java coordinate system), or -1 if the shortest rotation is in the opposite direction (clockwise). If p is already colinear, the return value is -1 if it lies beyond the first point, 0 if it lies in the segment, or 1 if it lies beyond the second point. If the first and second point are coincident, this returns 0.

Parameters: px the reference x coordinate py the reference y coordinate

Returns: the relative rotation direction

See Also: Line2D